Help carb problem

[wa4ko]

Bought a 55 Bird that has a 302 in it and was barely running, and not idling at all.
Compression is good all around, First I removed all vacuum lines and blocked them, replaced the pcv valve. All plugs look good.
Replaced fuel pump 7 lbs pressure and good flow, Rebuilt the Motorcraft 2150 ( 108 ) carb with 48 jets, Replaced the entire ignition system, distributor, coil, wires. drained and replaced the gas.
Start the car with the choke closed runs great, knock it down one notch still runs great 19 inches of vacuum solid. After about 5 minutes the choke starts to open and it starts fluttering and missing, if I hold the choke almost closed it will run great, but when it opens it will not keep running. I took the carb apart again, all clean and open. Nothing I have done has changed the problem at all?? It does not seem to be getting enough fuel to the idle setup in the carb, the screws start at 1 1/2 out and tried from 0 to 4 turns only slight changes. Don't want to buy a carb if I do not need it but do you have any other ideas I missed??
Larry

[wa4ko]

I think I found the problem, the throttle shaft is loose and sucking in air.
I will let you know if this does not work out
Larry

[fbcoach68]

Did the throttle shaft fix the problem?

[Frank The Plumber]

7 psi fuel pressure is too high, you should back it down to 5, or even 4.5, did your carb have screens on the opposite side of the float needle valves? When you were settings the mixture screws were you watching your vac ? What did the vac do when the choke opened? Can you rag the shaft to get a seal?

[wa4ko]

OK Guys
I determined the problem was with the carb leaking air around the throttle shaft
and traded it for a rebuilt carb. Guess I was right, purring like a kitten now no
problems left. Just wanted all to know and thanks
Larry